1. Field of the Invention
This invention pertains to revolving doors. More particularly this invention relates to revolving door security and safety systems.
2. Description on the Prior Art
Automatic and electrical revolving doors have been in use for many years. Electrical revolving doors facilitate rotation particularly in applications where the stack pressure, that is, the pressure differential from the interior to exterior space on opposite sides of the revolving door, is significant. In some applications, mechancial gearing makes manual rotation difficult. Braking systems have also been used in connection with revolving doors for use in emergency events and to prevent unauthorized passage.
Security is often important to prevent unauthorized access to various areas. In some situations, it is necessary to prevent exiting from the revolving door after one has already entered into a security region. It would be desirable to provide such selectively directed access without the necessity and costs of guard stations.